Boeing Sonic Cruiser ousts 747X
GUY NORRIS/LOS ANGELES
EMMA KELLY/LONDON
BOEING HAS shelved plans to develop die 747X and Longer
Range 767-400ER in favour of a
high-speed, subsonic transport
which could enter service as early
as 2006 and is designed to fly at
speeds up to Mach 0.98.
Airlines, however, have res
ponded with a mixed reaction.
While some raise operational, eco
nomic and technical concerns, oth
ers see an immediate need for die
aircraft, dubbed the "Sonic
Cruiser" by Boeing Commercial
Airplanes president and chief
executive Alan Mulally.
Early studies are focused on a
twin-aisle variant seating 225,
though die airlines are pressing
Boeing to look at a larger version
seating 2 5 0-3 00 passengers. Small-
er variants, possibly single-aisle
designs, are also being considered
for versions seating less than 200.
Sized around the current 767-300
span for gate suitability, die first
study version is expected to be
slightly under 60m (200ft) long
widi a maximum take-off weight
around 204,300kg (450,0001b).
The twin-engined aircraft is being
designed around 777-200/300
powerplants to shorten die design
cycle, diough the unusual semi-
recessed mountings will require
s-shaped inlet ducts.
The aircraft is expected to have a
circular, constant section fuselage
sized initially between the 5.03m
width of the 767 and die 777's
6.2m. Like die 777 it will have
fly-by-wire controls and a 777-
style flightdeck, prompting some
consideration of cross-crew quali
fication widi die fbig twin. This,
along widi reduced flight crew
costs because of shorter flight
times, forms one of die low-operat
ing cost goals established for die
new design under die 20XX
project which spawned die sonic
cruiser. Boeing adds diat die design
will have "at least partial" relaxed
stability, and will incorporate a
prominenfcset of foreplanes on die
forward fuseiage.
The Sonic Cruiser is equipped
widi a double-delta, or "cranked
arrow", wing combining a high-
Boeing is flying its "Sonic Cruiser" idea after shelving its 747Xplans
speed inboard section and a higher
aspect ratio outboard section
reminiscent of conventional Boe
ing wings. The outboard section
has leading and trailing edge flaps
for low-speed, and features die
raked tip used on the 777 and 767-
400ER. The aircraft's twin tails,
slightly canted inwards, are mount
ed on die inboard of die engine
nacelle, which project from
mounts within die wing.
The configuration is designed
to cruise at Mach 0.95 to 0.98, at
altitudes between 40,000ft
(12,2Q0m) and ,50,000ft. This
would reduce flight times by more
than lh for everf/5,000km flown,
cutting trans*dantic trip times by
more than 2h and transpacific
flights by more than diree.
The airline working group pro
viding input to the design is
believed to include American
Airlines, All Nippon Airways,
British Airways, Cajhay Pacific,
Japan Air Lines, United Airlines
and Singapore Airlines (SIA).
One prominent Asian member
of the group, however, says that die
design is not necessarily a response
to airline requirements. Instead,
die airline believes Boeing was
driven to develop a new aircraft in
response to small market forecasts
for the 747X - 70 to 80 aircraft over
nine years - and high programme
costs. And it suggests the final nail
in die 747X coffin is an expected
A3 80 order from Lufthansa. The
German flag-carrier is reported to
have signed a letter of intent with
Airbus for 10 firm plus 15 options.
The reduced flight times on
Asian-Europe routes could cause
scheduling problems, the airline
adds. Anodier airline source says,
however, that the aircraft would
provide operational advantages on
US West Coast-to-Europe routes.
Emirates, meanwhile, has raised
fuel consumption, economic and
operational issues. Group manag
ing director Maurice Flanagan says
that die Sonic Cruiser would not be
suitable for Emirates on the Dubai-
London route, for example, due to
slot constraints at Heathrow,
where the greater capacity A3 80
makes more sense - an issue which
would affect a number of carriers at
many slot-constrained airports.
ALTHOUGH Boeing's "Sonic Cruiser" con
cept underlines its belief in the fragmentation
phenomenon, the compammaintains its "slow
down" on the 747X does not mean it is com
pletely surrendering the large aircraft market
place to Airbus and the A380 family. "Our
current 747 and planned developments are great
competition for the A3 80," says Mike Bair, vice
president business strategy and marketing for
Boeing Commercial Airplanes. "However, if you
ask me will we have anything to compete against
it [the planned A3 80 growth variant] in the 600-
seater market, the answer is no."
Air Canada and SIA have reacted
favourably to the aircraft as long as
Boeing can deliver on the econom
ics. Air Canada president and chief
executive Robert Mlton says: "If I
was Airbus I'd be very worried",
while SIA chief executive Dr
Cheong Choong Kong believes
there is room for the A3 80 and die
Sonic Cruiser in SIAs fleet.
Mulally says the Sonic Cruiser is
designed as a long range "comple
ment" to the 767, not as a replace
ment. The re-engined 767-400ER
has therefore been effectively
killed by die decision, as has the
stretched 747X family. Boeing says
it is still "protecting the ability to
do a larger 747" but says the
emphasis will shift to improve
ments to the current aircraft.
Airbus says the 747X cancella
tion "does not come as a surprise",
adding its 62 A3 80 orders support
market calls for an all-new aircraft.
Airbus sources say the higher speed
of the SonicCruiserwould produce
only a small advantage in flight
times on medium-haul routes for a
disproportionate increase in
weight and fuel costs. •
Boeing's revised growth plan for the 747
encompasses a potential further gross weight
step beyond the 413,140kg planned for the
Longer Range 747-400 already under develop
ment. "We're looking at doing something with
the engines to reduce fuel burn and noise, as well
as aerodynamic improvements, including the
trailing edge wedge and different wingtip treat
ments - such as the raked tip," adds Bair. The
revised plan, believed to be provisionally dubbed
the 747-500X, combines cabin interior, flight-
deck, systems and aerodynamic upgrades
earmarked for the 747X.
FLIGHT INTERNATIONAL 3 - 9 April 2001 7